Oven for baking, heating or keeping bakers&#39; wares at a constant temperature



March 29, 1960 Filed 001;. 19, 1956 F. H. LEEUWRIK OVEN FOR BAKING, HEATING 0R KEEPING BAKERS W 2,930,333 ARES AT A CONSTANT TEMPERATURE 2 Sheets-Sheet 1 INVENTOR.

div-rem March 29, 1960 F. H. LEEUWRIK 2,930,333

OVEN FOR BAKING. HEATING OR KEEPING BAKERS WARES AT A CONSTANT TEMPERATURE Filed Oct. 19, 1956 2 Sheets-Sheet 2 carried at the outside of the tunnel.

OVEN FOR BAKING, HEATING on KEEPING BAKERS WARES AT A CONSTANT TEM- PERATURE Frederik H. Leenwrik, Zaandam, Netherlands, assignor to Koninklijke Verkade Fabrieken N.V., Zaandam, Netherlands, manufacturers, a limited-liability comparty of the Netherlands 1 t Application October 19, 1956, Serial No. 617,191 Claims priority, application Netherlands October 21, 1955 3* Qlairns. (Cl. rev -s6 The present invention relates generally to'an oven for baking or heating bakers wares, or for keeping the same at a constant temperature, for example, for bakingor causing the rising of rusk or crackers, and is particularly directed to an even of the kind having an inlet and an outlet at its opposite ends with a tunnel extending therebetween, and with a conveying device arranged in the tunnel to transport the bakers wares through the tunnel from the inlet, to the outlet alonga substantially horizontal straight path.

Ovens of the above described character'are known and,

7' tunnel wall, and such sealing means permit the -leakage erably at least twovertically superposed tunnels provided in such known ovens, the conveying device consists, in

general, of an endless member, for example, a chain or a' veying chain or belt, thev same can be repaired only with considerable difliculty. Further, in the known ovens, considerable heat is lost due to the fact that the conveying chain or belt leaves the outlet of the tunnela't a high temperature and reenters the inlet of the tunnel at a much lower temperature.

An object of the present invention is to provide an oven of the described character in which the'above mentioned disadvantages of the existing or known ovens are eliminated.

In accordance with an aspect of the invention, the above mentioned disadvantages of the existing ovens are avoided by using a conveying mechanism which, while known as such, has never been applied to an ovenof the described character. According to the invention, the conveyin'g device or mechanism comprises at least two supporting deviceswhich are movablerelative to each other both in the direction ofthe longitudinal axis of the tunnel and in the vertical direction over distances which are small in comparison with the dimensions of the tunnel in the related directions, with the supporting devices being effective to alternatively support baking plates or pans carrying the bakers Wares, and with at least one of the supporting devices being movable with respect to the tunnel and being substantially immovably connected, by means of bearing members, to a bearing device'which is The bearing members extend through the wall ofthe tunnel, and a driving device is arranged outside the tunnel for "driving the bearing device in order to move the movable supporting device so that the baking plates are lifted from the other supporting device and shifted horizontally in the direction toward the outlet of the tunnel prior to being lowered upon the other supporting device.

In a preferred embodiment of he invention, the bear ing members extending from the inside to the outside of with similar supporting devices whichare movable with respect to the related tunnels, and with such supporting superposed tunnels are usedforbaking or heating putposes, the several tunnels can be covered by a common insulating layer. Further, the side walls of each tunnel can have channels or apertures therein to permit the escape of'water vapor'developed during the passage of the bakers wares therethrough, so that a relatively small oven or chamber can be employed for causing the risingof dough, with such relatively small oven or chamber nevertheless having a very large capacity. I As distinguished from the above, when chains or belts are employed for conveying the bakers wares through the tunneloven, as is the case in known ovens of the described, character, great difficulties are encounteredin arranging a number of tunnels one above the other, as each which is to be read in connection with the accompanying drawings forming a part hereof, and wherein: Fig. 1 is a longitudinal sectional view of a part of an oven embodying the present invention;

Fig. 2' is a transverse sectional view taken along the line IIIi of Fig. l; V

Fig. 3 is a sectional view similar to that of Fig. 2, but on an enlarged scale and showing another embodiment of the invention, wherein several'baking'chambers or tunnels. are disposed in vertically superposed relationship;

and

Fig. 4 is an enlarged, fragmentary sectional view taken along the line IV-IV of Fig. 3.

Referring initially to Figs. 1 and there illustrated, the oven includes an'open ended tunnel of uniform rectangular crosssection having side walls 1 and 2, a bottom wall 3 and a top wall 4. 'Thewalls 1, 2, 3and4of the tunnel are covered by a continuous'insulating layer 5 (Fig. 2). v

Horizontally arranged rows of brackets 6 are secured to the inside surfaces of the side walls 1 and 2, and each row of brackets 6 carries a horizontal rail 8 which extends along the entire length of the tunnel. The brackets 6 and the rails 8 together constitute a first supporting de vice which is fixed relative to the tunnel.

In the vicinity of each rail 8, there Is an angle iron which extends parallel to the adjacent rail Sand is substantially longitudinally coextensive with the latter. Each angle iron 10 has a vertically directedv leg anda horizontally directed leg extending from the lower edge of the vertically directed. leg in the direction away from the adjacent side wall 1 or 2 of the'tunnel.

The angle irons 10 are suspen ded from bearingfnembers 11 and 12 which are in the shape of vertical suspension rods disposed adjacent the tunnel side walls 1 and {2, respectively, and gusset plates 13 are" secured to the angle irons 10 and the bearing members 11 and 12in order'to ensure that the angle irons 10 will remain perpendicular Patented Mar. 29, 1960 2'of'thc drawings, it will be seen that, in the embodiment of the invention to the related bearing members. The angle irons 10 constitute a second supporting device which, together with the first supporting device, that is, the brackets 6 and rails 8, constitute a conveyor device, wherein the first and second supporting devices are movable with respect to each other, but only one of the supporting devices, that is, the second supporting device formed by the angle irons 10, is movable with respect to the tunnel.

The bearing members 11 and 12 project upwardly through slots 14 in the top wall of the tunnel so that the bearing members 11 and 12 are free to move both vertically and horizontally with respect to the tunnel, and leakage through the slots 14 is substantially avoided by seals comprising sliding members 15 which cover the slots 14 and are'slidable over the latter in the longitudinal direction of thetunnel within suitable guides 16. Each sliding member 15 has a suitable vertical bore 17 in which the related bearing member 11 or 12 is vertically movable. Thus, each bearing member 11 or 12 can move vertically in the bore 17 of the related sliding member 16 while the latter continues to seat on the top wall 4 of the tunnel and thereby cover the slot 14, while the sliding member 15 can move horizontally with the related bearing member 11 or 12, while still covering the slot 14, thereby to prevent any harmful leakage of gas and vapor through the slot 14.

The upper ends of the bearing members 11 and 12 which are situated above the tunnel have forks 18 and 19, respectively, in which rolls are rotatably mounted. At locations below the forks 18 and 19, the bearing members 11 and 12 are connected by longitudinal rods 36 and 37, respectively. The longitudinal rods 36 and 37, the forks 18 and 19 and the upper end portions of the bearing members 11 and 12 together constitute a bearing device for the supporting device formed by the angle irons 19.

The rolls 20 mounted in the forks 18 and 19 ride on horizontal rails 21 and 22, respectively, so that the angle irons 10 are suspended from the rails 21 and 22, while the latter are free to move horizontally with respect to the angle irons 10. The rails 21 and 22 are connected to each other by horizontal, laterally extending rods 23 and 24, and each of the rods 23 and 24 carries two rollers 25 which are supported by immovable cams 26 having inclined, parallel planes on their cam faces engaged by the rollers 25.

A shaft 27 is rotatably mounted in bearings which are fixedly arranged with respect to the tunnel, and the shaft 27 is driven by a motor through a gear transmission (not shown). A radial cam 28 is fixed on the shaft 27 and is engaged, at its periphery, by a cam follower roller 29 mounted on a lever 30 which is pivoted, at its lower end,

on a pin 31 fixedly mounted on the top wall 4 of the tunnel. The upper end of lever 30 is hingedly connected, as at 32, to one end of a rod or link 33 which, at its other end, is pivotally connected to the rod 23 extending between rails 21 and 22. When shaft 27 is rotated, cam 28 rotates therewith, and the lever 30 is made to oscillate about the pivot pin 31 in a plane parallel to the tunnel side walls 1 and 2 by reason of the rolling engagement of roller 29 with the periphery of cam 28.

Assuming that the shaft 27 rotates in the direction of arrow 34 on Fig. 1, that is, in the clockwise direction, starting from the position of cam 28 and lever 30 shown in Fig. 1, then roller 29 and lever 30 will remain in the position illustrated in Fig. 1 for slightly less than half a revolution of shaft 27 and, thereafter, will move toward the left to a position determined by the portion of the cam having a relatively small radial dimensiomwhere lever 30 and roller 29 will remain for slightly less than half a revolution of shaft 27. Thereupon, roller 29 and lever 30 will be returned to the position shown in Fig. 1, and the described cycle of movement of roller 29 and lever 30 will be repeated as rotation of the shaft 27 continues. During such oscillation of roller 29 and lever 30, the angular displacement of the latter about pivot pin 31 effects back and forth movement of the rails 21 and 22. By reason of the engagement of rollers 25 with the inclined cam faces of cams 26, the back and forth movement of rails 21 and 22 will be accompanied by a rising and falling movement of the latter. Consequently, the rolls 20 will move up and down with the rails 21 and 22 and the horizontal legs of the angle irons 10 will move up and down therewith between an elevated position, shown in Fig. 2, where the horizontal legs of the angle irons 10 are disposed above the level of the top edges of rails 8 and thereby support the baking plates 35, and a depressed position, in which the horizontal legs of angle irons 10 are located below the level of the top edges of rails 8'so that the baking plates 35 are then supported by the rails 8.

Since the bearing members 11 and 12 are suspended from the rails 21 and 22 by way of the rolls 20, the hearing members 11 and 12 need not participate in the horizontal component of the movement of the rails 21 and 22 and, consequently, if desired, an independent horizontal component of motion can be imparted to the bearing members 11 and 12. In order to impart the independent horizontal component of motion to the rails 21 and 22, the longitudinal bars 36 and 37 are connected by a cross bar 38, and the shaft 27 further carries an eccentric disc 39 provided with an annular groove 40. A roller 41A runs in the groove 40 and is rotatably carried by a lever 41 which, at its bottom end, is pivotally mounted on a pin 42 which is fixedly mounted on the top wall of the tunnel. The upper free end of lever 41 is pivotally connected to one end of a link or bar 43 which, at its other end, is pivotally connected to the cross bar 38. Thus,

-as the eccentric disc 39 is rotated with the shaft 27, the

lever 41 is oscillated about the pivot 42, and the oscillating movement of lever 41 is converted into horizontal movement of the bearing members 11 and 12 by way of the link or bar 43 connecting lever 41 to cross bar 38.

The cam 28 and the eccentric disc 39 are angularly related to each other on the shaft 27 so that, when the shaft is rotated in the direction of arrow 34, the eccentric disc 39 causes the supporting device formed by the angle irons 10 to move to the right and to the left, as viewed in Fig. 1, when such supporting device is in its above described elevated and depressed positions, respectively. Consequently, during the movement of the angle irons 10 toward the right, the baking plates 35 which are then supported on the elevated angle irons 10 will also move to the right, while during the return movement of the angle irons 10 to the left, such angle irons are in their depressed position so that the baking plates 35 rest on the supporting device formed by the fixed rails 8 and accordingly do not participate in the return horizontal movement of the angle irons 10. Hence, the baking plates 35 are intermittently moved from the inlet of the tunnel, through the tunnel to the outlet .of the latter, while the supporing devices on which the baking plates alternatively rest during such movement not only do not leave the oven tunnel but are movable back and forth only over a restricted distance and therefore remain under practically the same temperature conditions. In this way, condensation and corrosion of the conveyor device are restricted to the greatest possible extent and the supporting devices for the btking plates do not cool down with the consequent losses 0 heat.

The cam 28, eccentric disc 39, levers 30 and 41. bars 33 and 43, rails 21 and 22, cross bars 23 and 24 and the inclined planes of cams 26 taken together constitute a driving device for the movable supporting device formed by angle irons 10.

Referring now to Figs. 3 and 4, it will be seen that the oven constructed in accordance with the embodiment of the invention there illustrated comprises three tunnels 50, 51 and 52 which are vertically superposed and enveloped by a single insulating layer 53. The superposed tunnels 50, 51 and 52 have common side walls 54 and 55, and

' 52 in the manner hereinafter described in detail.

the top tunnel 50 has atop wall 56- .while the bottom tunnel 52 has a bottom wall 57 which form the top and bottom walls, respectively, of the combined tunnels.

Further, partition walls 58 and 59'extend horizontally flue gases can pass so that heat will be radiated from the surfaces of such walls.

Each of the walls 57, 58 and 59 has laterally extending rows of uprights or posts 61 fixed to the upper surface of the wall, for example, as by welding, and supp rting, at their upper ends, parallel, spaced apart rods 62 which extend horizontally in the longitudinally directionsof the related-tunnels 50, 51 and 52. The bars or rods 62 may be secured to the related posts'or uprights 61 by welding,

and the series of bars or rods 62in each of the tunnels 50, 51 and 52 constitute the first supporting device ofthe respective conveyor mechanism in the related tunnel, and

thus correspond to the rails S Which are fixed relative to the tunnel in the embodiment previously described with reference to Figs. '1 and 2;

In the embodiment of Figs. 3 and 4, the conveyor mechanism in each of the tunnels 50, 51 and 52 further comprises a second supporting device corresponding to the angleirons 10 of the first described embodiment and comprising a series of parallel, horizontal, longitudinally directed bars or rods 63 which are arranged intermediate the fixed bars 62 in the related tunnel, and which are movable vertically and also horizontally, in the direction of the longitudinal axis of the tunnel, relative to the tunnel, and hence, also relative to the fixed bars'62.

The movable bars 63 in each of the tunnels 50, 51 and 52 are supported by posts or uprights 64-,which are secured thereto, as by welding, and which depend from the bars 63 in laterally directed rows which are suitably spaced from the rows of posts 61 in the longitudinal di-- rection-of the tunnel, as is apparent in Fig. 4. The

lower ends of each row of posts 64 are secured, as by welding, to a related horizontal, laterally extending bar 65 which passes under the fixed bars or rods 62 and is movable both vertically and horizontally, in the direction-of the longitudinal axis of the related tunnel, in the clearances between the fixed rods 62 and the top surface ofthe related wall 57, 58 or 59.] As is apparent in Fig.

. 3, the posts 64 supporting the rods 63 have, a height which is substantially less than the height of the posts 61 supporting the rods 62 so that the vertical movement of t the related laterally extending bar 65 permitted within the above mentioned clearances under the fixed bars or rods 62 is sufiicient for vertical displacement of the movable rods 63 between the depressed position, illustrated in Fig. 3, where the rods 63 aredisposed at a level below that of the fixed rods 62, and an elevated position, where the rods 63 are disposed at a level above that of the fixed rods 62 in the related tunnel.

The lateral bars 65 inthe several tunnels 5t), 51 and 52 lie in the same vertical planes and, at their opposite ends, are rigidly attached, as by welding, to common bearing members 66 and 67, respectively, which are in the form of vertical suspension rods extending loosely through slots 68, 69 and 70 formed in top wall 56 and partition walls '58 and 59, respectively, of the tunnel structure. The slots 68, 69 and 70 are elongated in the longitudinal direction of the tunnels to permit horizontal movement of the bearings members 66 and 67 in thedirection of the longitudinal axis of the tunnel structure, as well as to permit vertical movement of the bearing members 66 and 67 for producing the desired horizontal and vertical movements of y the several tunnels 50, 51 and 52.

The bearing members 66 and 67 project upwardly above the top wall 5670f thetunnel and correspond to the'bear- 7 ing members 11 and 12 of the first describedembodime'nt of the invention, with the necessary horizontal and vertical movements being imparted to the bearing members 66 "and 67'by a"'me'chanism which is the same as that previously described withreference to Figs. 1 and 2 of i the drawings. Thus, asshown in,Fig. 3, the bearing members 66 and 67 have forks 18a and 19a, respectively, at their upper ends, inwhich rolls 20a are rotatably mounted, with 'such rolls 20a riding on movable rails 21a and 22a. The rails 21a and 22a are connected by laterally extendingrods, of which'only the rod 23a appears in Fig. 3, and such rods carry rollers 25a which ride on the inclined planes of cam' members 26a so that, -whe'n the rails 21a and 22a are horizontally displaced,

such horizontal. displacement is accompanied by vertical displacement of the rails 21a and 22a which is transmitted, by way-of the rolls 20a, to the bearing members 66 and '67. The horizontal displacement of the rails 21:: and22a is effected by a link or bar 33a which is pivotally connected to the cross bar or rod 23a and which, as in the embodiment of Fig. 1, is also pivotally connected to a rockable lever carrying a cam follower roller which engages the periphery of a radial cam fixed on a rotated shaft,'and corresponding to the lever 30, earn follower roller :29, cam 28 and shaft 27 of the first described embodiment. V

" Further, as in the first described embodiment of the invention, the desired horizontal movements of the bearing members 66 and 67 are'obtained by providing longi tudinally extending bars 36a and 37:; which connect the bearing members 66 and 67, respectively, at the opposite sides of the tunnel structurepand which are, in turn, conslots 68 is provided with a seal generally identified by i nected by alat'erally extending cross rod 38a to which a link or bar 43a is pivotally connected. 'The link or bar 43a is also'pivotally connected to a rockable lever carrying a roller whichengages in a groove of an eccentric disc fixed on a rotated drive shaft (not shown) and corresponding to the lever 41, roller 41A, groove 40 and eccentric disc 39 on shaft 27 in the embodiment 'of Fig. l. V a

As in the first :described embodiment, the horizontal and vertical movements imparted to the bearing members 66 and 67 of the embodiment illustrated in Figs. 3 and 4 are 'coordinatedso that, when the movable-rods 63 are moved vertically to their elevated positionstin each tunnel at levels above the related fixed rods 62,

the movable rods 63 are then displaced horizontally in the direction toward the outlet ends of the tunnels and,

'when the rods 63 are displaced vertically to their de-.' 7

pressed positions, where they are disposed at a level below thatof the related fixed rods 62, the movable rods 63 are then displaced horizontally in the direction away from the outlet ends of the tunnels. Thus, baking plates placed within the several tunnels 50, 51 and 52 will be intermittently advanced through the tunnels from the inlet to the outlet ends thereof. p

In order to prevent the escape of excessive amounts of gas or vapor from the oven through the slots 68 provided in the top wall 56 for the extension of the bearing members 66 and 67 therethrou'gh, each of the the reference numeral 71 and, if desired, as shown in Fig. 3, the side walls 54 and 55 can be provided with inwardly directed flanges 72 and 73 disposed above top wall 56 near the upper surface of the insulation layer 53 and having slots 74 through which bearing members 66 and 67 also loosely extend, with additional seals" the security against leakage of gas or vapor from the oven,

In order to ensure that the baking conditions in the several tunnels 50, 51 and 52 will be independent of each other for obtaining the practically uniform baking of the products in the several tunnels, the slots 69 and 70 in the partition walls 58 and 59, respectively, are also provided with seals which are generally identified by the reference numerals 76 and 77, respectively.

It will be apparent that the seals 71, 75, 76 and 77, while being efiective to prevent the substantial leakage of gas or vapor through the associated slots, must nevertheless permit the above described horizontal and vertical movements of the bearing members" 66 and 67 which are necessary for the operation of the conveyor mechanisms in the several tunnels. Thus, the seals 71, 75, 76 and 77 are similar to the seals provided in the embodiment of Figs. 1 and 2 in association with the slots 14 thereof. Accordingly, as shown in Figs. 3 and 4, each of the seals 71, 75, 76 and 77 includes an elongated sliding member 15a which covers the related slot and is slidable over the latter in the longitudinal direction of the oven within guides 16a. The sliding member 15a is further provided with a vertical bore 17a in which the related bearing member 66 or 67 is vertically slidable with a close fit therebetween. Thus, each bearing member 66 or 67 can move vertically relative to the sliding members 15a of the related seals, and such sliding members 15a can move horizontally with the related bearing member 66 or 67 during horizontal displacement of the latter while continuing to cover the related slot of the partition wall, top wall or top flange 72 or 73.

Since the movable supporting devices constituted by the rods 63 in the several tunnels'50, 51 and 52 are synchronously displaced by a common set of bearing members 66 and 67, it is apparent that only a relatively limited number of such bearing members is required so that the number of slots formed in the top wall of the oven and in the partition walls between the several tunnels are minimized and the necessary sealing of such slots can be easily effected, in the manner previously indicated.

Although illustrative embodiments of the invention have been described in detail herein with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments, and that various changes and modifications may be effected therein without departing from the scope or spirit of the invention, except as defined in the appended claims.

What I claim is:

1. An ovenfor baking, heating or keeping bakers Wares, such as rusk or biscuits, at a constant temperature, comprising a wall structure defining a plurality of vertically superposed, horizontally extending straight tunnels each having an inlet and an outlet at the opposite ends for the passage therethrough of baking plates carrying the bakers wares; a conveying device in each of said tunnels including at least two supporting devices for the baking plates, at least one of said supporting devices being movable with respect to the related tunnel, connecting members substantially immovably connecting said one movable supporting device of each conveying device with the corresponding movable supporting device of the other conveying devices, a bearing device located outside of said tunnels, bearing members extending through said wall structure and substantially immovably connecting said bearing device to said connected together movable supporting devices, and a driving device located outside said tunnels for moving said bearing device together with the supporting devices connected thereto in the direction of the longitudinal axes of the tunnels and also in the vertical direction over a distance which is small in comparison with the dimension of each tunnel in the respective direction, the driven movable supportingdevice in each tunnel being effective to periodically lift baking plates from the other related supporting device and to shift the lifted baking plates horizontally toward said outlet prior to lowering the baking plates onto said other supporting device so that baking plates in said tunnelsare simultaneously intermittently moved from the inlets to the outlets thereof.

2. An oven as in claim 1; wherein said wall structure includes partitions between the vertically superposed tunnels, said partitions having openings therein through which said connecting members movably project, and sealing means at said openings to permit the leakage through the latter of only negligible quantities of gas and vapour.

3. An oven as in claim 2; further comprising an insulating layer covering said tunnels, said bearing members projecting outwardly through said sealing means, and said bearing device being located outside said insulating layer above the uppermost tunnel.

References Cited in the file of this patent UNITED STATES PATENTS 

